1) Field of the Invention
The present invention relates to a technology for recognizing contents of a video and a technology for recording a video.
2) Description of the Related Art
A programmed recording device records video images of a program at a scheduled time. Such a programmed recording device recognizes contents of a video that is being recorded from various features of the video image and based on those features, recognizes whether the program that is being recorded has been prolonged. If so, it alters the starting and ending of recording.
A typical conventional programmed recording device includes a video-content recognizing unit, a program information setting unit, which sets information related to programs intended to be recorded, and a recording time control unit, which collates the contents recognized by the video-content recognizing unit and the information set by the program information setting unit and controls the starting and ending of a recording. The video-content recognizing unit includes a feature detecting unit, which detects features of image signals, a knowledge base unit, which contains a knowledge base related to the features of the image content, and a feature verifying unit, which collates the detected features and the knowledge base.
Such a conventional technology has been disclosed in, for example, Japanese Patent Laid-Open Publication No. H6-309733.
However, in the conventional programmed recording devices, the knowledge base unit, which contains the knowledge base related to the features of the video image content, has to be prepared in advance. As a result, it is difficult to provide feature data of video image contents related to a new program. Consequently, the accuracy of feature detection from the video image content becomes low, leading to a failure to record a new program.
For example, assume programmed recording has been set for a relay of a baseball match. When the knowledge base unit receives new video image signals such as when a baseball match is relayed from a different stadium, the uniform of the baseball team has changed, or the screen layout of the broadcasting station relaying the match changes, etc., these signals are not recognized as video image contents of the baseball relay scheduled to be recorded. As a result, no recording is performed.
One approach to enhance the accuracy is to update the contents of the knowledge base unit. However, with a current trend towards multi-channel broadcasting, the quantity of data involved and the frequency of data updating will become inordinately large and the volume of parameter data of the knowledge base unit will also increase. The increased parameter data results in a higher probability of erroneous detection, which decreases the accuracy of detection.